Recent researches in our laboratory have shown that a major function of energy input in oxidative phosphorylation is to bring about release of non-covalently bound ATP from the mitchondrial membrane. Most likely this occurs through energy-linked conformational change. Our principal efforts during the coming year will be directed towards further investigation of the characteristics of this new concept for oxidative phosphorylation. Studies will include the affect of various metabolic inhibitors and conditions on the formation of the firmly bound ATP at the coupling site and on the associated 018 and p32 exchanges. Included will be rapid mixing and quenching studies to assess the kinetic competency of the firmly bound ATP as an intermediate for the oxygen exchanges and oxidative phosphorylation. Studies will be extended to include chloroplast and chloroplast particles to assess if similar energy-linked reactions appear to be occurring with this system. As a further probe of conformational coupling, the affect of cross- linking agents on the various energy-linked reactions of mitochondria and of sarcoplasmic reticulum membranes will be assessed. By cross linking it may be possible to block critical conformational changes and detect residual partial reactions. Other related studies will be towards better chemical characterization of the phosphorylated proteins in the transport ATPases. Considerable controversy still exists about the nature of the amino acid furnishing the carboxyl group. We have developed a new method based on a borohydride reduction technique, and application to both the sarcoplasmic reticulum and to microsomol Na plus, K plus - ATPase is proposed. Some studies will be continued on multiple isotopic probes of the glutamine synthetase and pyruvate kinase reaction, as time and budgets permit. Emphasis will be possible detection of new modes of control of catalysis.